From: "Christian König" <christian.koenig@amd.com>
To: Jason Gunthorpe <jgg@ziepe.ca>
Cc: "Leon Romanovsky" <leon@kernel.org>,
"Sumit Semwal" <sumit.semwal@linaro.org>,
"Alex Deucher" <alexander.deucher@amd.com>,
"David Airlie" <airlied@gmail.com>,
"Simona Vetter" <simona@ffwll.ch>,
"Gerd Hoffmann" <kraxel@redhat.com>,
"Dmitry Osipenko" <dmitry.osipenko@collabora.com>,
"Gurchetan Singh" <gurchetansingh@chromium.org>,
"Chia-I Wu" <olvaffe@gmail.com>,
"Maarten Lankhorst" <maarten.lankhorst@linux.intel.com>,
"Maxime Ripard" <mripard@kernel.org>,
"Thomas Zimmermann" <tzimmermann@suse.de>,
"Lucas De Marchi" <lucas.demarchi@intel.com>,
"Thomas Hellström" <thomas.hellstrom@linux.intel.com>,
"Rodrigo Vivi" <rodrigo.vivi@intel.com>,
"Kevin Tian" <kevin.tian@intel.com>,
"Joerg Roedel" <joro@8bytes.org>, "Will Deacon" <will@kernel.org>,
"Robin Murphy" <robin.murphy@arm.com>,
"Felix Kuehling" <Felix.Kuehling@amd.com>,
"Alex Williamson" <alex@shazbot.org>,
"Ankit Agrawal" <ankita@nvidia.com>,
"Vivek Kasireddy" <vivek.kasireddy@intel.com>,
linux-media@vger.kernel.org, dri-devel@lists.freedesktop.org,
linaro-mm-sig@lists.linaro.org, linux-kernel@vger.kernel.org,
amd-gfx@lists.freedesktop.org, virtualization@lists.linux.dev,
intel-xe@lists.freedesktop.org, linux-rdma@vger.kernel.org,
iommu@lists.linux.dev, kvm@vger.kernel.org
Subject: Re: [PATCH v3 3/7] dma-buf: Document RDMA non-ODP invalidate_mapping() special case
Date: Wed, 21 Jan 2026 14:52:53 +0100 [thread overview]
Message-ID: <8a8ba092-6cfa-41d2-8137-e5e9d917e914@amd.com> (raw)
In-Reply-To: <20260121131852.GX961572@ziepe.ca>
On 1/21/26 14:18, Jason Gunthorpe wrote:
> On Wed, Jan 21, 2026 at 10:17:16AM +0100, Christian König wrote:
>> The whole idea is to make invalidate_mappings truly optional.
>
> But it's not really optional! It's absence means we are ignoring UAF
> security issues when the exporters do their move_notify() and nothing
> happens.
No that is unproblematic.
See the invalidate_mappings callback just tells the importer that the mapping in question can't be relied on any more.
But the mapping is truly freed only by the importer calling dma_buf_unmap_attachment().
In other words the invalidate_mappings give the signal to the importer to disable all operations and the dma_buf_unmap_attachment() is the signal from the importer that the housekeeping structures can be freed and the underlying address space or backing object re-used.
Regards,
Christian.
>
> Given this I don't want to loose the warning log either, the situation
> needs to be reported..
>
> Jason
next prev parent reply other threads:[~2026-01-21 13:53 UTC|newest]
Thread overview: 40+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-01-20 14:07 [PATCH v3 0/7] dma-buf: Use revoke mechanism to invalidate shared buffers Leon Romanovsky
2026-01-20 14:07 ` [PATCH v3 1/7] dma-buf: Rename .move_notify() callback to a clearer identifier Leon Romanovsky
2026-01-21 8:33 ` Christian König
2026-01-21 8:41 ` Leon Romanovsky
2026-01-20 14:07 ` [PATCH v3 2/7] dma-buf: Always build with DMABUF_MOVE_NOTIFY Leon Romanovsky
2026-01-21 8:55 ` Christian König
2026-01-21 10:14 ` Leon Romanovsky
2026-01-21 10:57 ` Christian König
2026-01-20 14:07 ` [PATCH v3 3/7] dma-buf: Document RDMA non-ODP invalidate_mapping() special case Leon Romanovsky
2026-01-21 8:59 ` Christian König
2026-01-21 9:14 ` Leon Romanovsky
2026-01-21 9:17 ` Christian König
2026-01-21 13:18 ` Jason Gunthorpe
2026-01-21 13:52 ` Christian König [this message]
2026-01-21 13:59 ` Jason Gunthorpe
2026-01-21 14:15 ` Christian König
2026-01-21 14:31 ` Leon Romanovsky
2026-01-21 15:39 ` Jason Gunthorpe
2026-01-20 14:07 ` [PATCH v3 4/7] dma-buf: Add check function for revoke semantics Leon Romanovsky
2026-01-20 14:07 ` [PATCH v3 5/7] iommufd: Pin dma-buf importer " Leon Romanovsky
2026-01-21 9:01 ` Christian König
2026-01-20 14:07 ` [PATCH v3 6/7] vfio: Wait for dma-buf invalidation to complete Leon Romanovsky
2026-01-20 20:44 ` Matthew Brost
2026-01-21 7:59 ` Leon Romanovsky
2026-01-21 10:41 ` Christian König
2026-01-21 10:44 ` Leon Romanovsky
2026-01-21 17:18 ` Matthew Brost
2026-01-21 9:20 ` Christian König
2026-01-21 9:36 ` Thomas Hellström
2026-01-21 10:55 ` Christian König
2026-01-21 13:31 ` Jason Gunthorpe
2026-01-21 15:28 ` Christian König
2026-01-21 16:01 ` Jason Gunthorpe
2026-01-21 19:45 ` Leon Romanovsky
2026-01-22 11:32 ` Christian König
2026-01-22 23:44 ` Jason Gunthorpe
2026-01-23 14:11 ` Jason Gunthorpe
2026-01-23 16:23 ` Christian König
2026-01-23 16:31 ` Jason Gunthorpe
2026-01-20 14:07 ` [PATCH v3 7/7] vfio: Validate dma-buf revocation semantics Leon Romanovsky
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